package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.User;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWork;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import jakarta.annotation.PostConstruct;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDateTime;
import java.util.Collections;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWork redisIdWork;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;
    private IVoucherOrderService proxy;

    //阻塞队列
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);

    private static final ExecutorService SECKILL_ORDER_EXECUTOR= Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        //3.启动一个线程，不断从阻塞队列中获取订单信息
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{

        @Override
        public void run() {
            while (true){
                try {
                    //1.从阻塞队列中获取订单信息
                    VoucherOrder order = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(order);
                    //2.保存到数据库
                    IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
                    proxy.save(order);
                } catch (Exception e) {
                    log.error("处理订单失败",e);
                }
            }
        }
    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();


        //创建锁对象
        RLock lock = redissonClient.getLock("lock:order：" + userId);
        //获取锁
        boolean islock = lock.tryLock();
        if (!islock) {
            log.error("不允许重复下单");
            return ;
        }
        try {
            //获取事物代理对象
             proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    private static final DefaultRedisScript<Long> SECKILL_SCRIPI;
    static {
        SECKILL_SCRIPI = new DefaultRedisScript<>();
        SECKILL_SCRIPI.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPI.setResultType(Long.class);
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPI,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString());
        //2.判断返回结果是否为0
        int r = result.intValue();
        if (r != 0){
            //2.1不为0代表没有购买资格
            return Result.fail(r == 1 ?"库存不足":"不能重复下单");
        }
        //2.2为0代表可以购买,把下单信息保存在阻塞队列
        //创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.3订单id
        long orderId = redisIdWork.nextId("order");
        voucherOrder.setId(orderId);
        //2.4用户id
        voucherOrder.setUserId(userId);
        //2.5优惠卷id
        voucherOrder.setVoucherId(voucherId);
        orderTasks.add(voucherOrder);
        //获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        return Result.ok(orderId);
    }
  /*  @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠卷
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())){
            return Result.fail("秒杀还未开始");
        }

        //3.秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())){
            return Result.fail("秒杀已经结束");
        }

        //4.判断库存是否足够
        if (voucher.getStock() < 1){
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();


        //5.分布式锁
        //创建锁对象---lua脚本解决原子性问题
       // SimpleRedisLock redisLock = new SimpleRedisLock("order："+userId, stringRedisTemplate);
        //用redisson获取可重试的互斥锁
        RLock lock = redissonClient.getLock("lock:order：" + userId);
        //尝试加锁
        boolean islock = lock.tryLock();
        if (!islock) {
            return Result.fail("不允许重复下单");
        }
        try {
            //获取事物代理对象
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }*/

    @Transactional
    public  void createVoucherOrder(VoucherOrder voucherOrder) {
        //一人一单
        Long userId = voucherOrder.getUserId();

            //查询订单
            Long count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();
            //判断是否存在订单
            if (count > 0) {
                //用户已经购买过了
                log.error("用户已经购买一次了");
                return ;
            }

            //5.扣减库存
            boolean success = seckillVoucherService.update()
                    .setSql("stock = stock - 1")
                    .eq("voucher_id", voucherOrder)
                    .gt("stock", 0)//乐观锁，以库存代替版本号
                    .update();
            if (!success) {
                //库存不足
                log.error("库存不足");
                return ;
            }
            save(voucherOrder);
    }

}